1. Field of the Invention
The present invention relates to a printer, and, more specifically, to an improvement in paper-near-end detection which is used for giving notification when a remaining amount of rolled-up paper (roll paper) becomes low.
2. Description of the Related Art
To implement paper-near-end detection in a conventional printer of a type in which roll paper is hung by a shaft of a paper holder to be supported in a housing for the roller paper (a paper housing), the printer is provided with: a turnable lever in the paper housing, the turnable member being capable of rotationally moving between a pressing position in which the turnable lever is brought into contact with the roll paper and a non-pressing position in which the turnable lever is separated from the roll paper, and biased toward the non-pressing position by a spring or the like; and a detector to detect that the turnable lever is in the non-pressing position.
The turnable lever and the detector are both provided in a printer body.
The turnable lever is biased to be positioned in the non-pressing position. When the turnable lever is brought into contact with a predetermined position in an end surface of the roll paper housed in the paper housing, the turnable lever is turned to the pressing position as a result of being pressed by the roll paper.
The predetermined position of the roll paper with which the turnable lever is brought into contact is set to be a position separated by a predetermined distance (a predetermined rolling radius) from the center portion of the roll paper in the radius direction.
As a result, when the remaining amount of the roll paper is large and the rolling radius is sufficiently large, the turnable lever is in the pressing position while being brought into contact with the end surface of the roll paper. On the other hand, when the remaining amount of the roll paper becomes low and the rolling radius becomes small, the turnable lever is separated from the end surface of the roll paper and is biased and rotationally moved to the non-pressing position. Then, the detector detects the non-pressing position of the turnable lever. As a result of this detection, notification of the remaining amount of paper and the like are made (Japanese Utility Model Application Laid-open Publication No. 56-128264).
Meanwhile, the related art described in Japanese Utility Model Application Laid-open Publication No. 56-128264 has a problem that the structure of a printer body becomes complicated because the turnable lever and the detector are integrally provided in the printer body.